Surface water purifying catch basin

ABSTRACT

The apparatus is a surface water purifying catch basin which uses a lamella separator to separate out fine sediment and a separate chamber to trap heavy debris, oil, and floating debris. The surface water enters an inlet chamber which is separated from a settling chamber by a divider wall that has a lower opening between the chambers and a higher overflow. The inlet chamber traps floating contaminates and those that are heavier than the water. The opening between the chambers permits the surface water to flow into and through the lamella separator. The catch basin exit is from the settling chamber, but the water can reach the exit only through the lamella separator that separates out the fine sediment in the water. All of the accumulated contaminates can be removed through access holes in the top of the catch basin.

BACKGROUND OF THE INVENTION

[0001] This invention deals generally with surface water purification,and more specifically with a catch basin which purifies surface waterthat flows through it.

[0002] As more land is being converted to commercial use, contaminationof surface water is becoming more of a problem. Not only does thetypical parking lot or street affect the natural flow of surface water,but it also significantly contaminates it. When walking through atypical parking lot or along a street it becomes apparent that suchsurfaces not only accumulate trash, but they also have numerous spillsof oil and other fluids from automobiles and trucks. Furthermore, suchcontamination is not limited to parking lots used for commercialpurposes. Parking lots for churches, schools and office buildings havethe same problems.

[0003] Although it is well understood that all such construction mustcontrol its surface water runoff quantity, it is not fully appreciatedthat the poor quality of surface water coming off a typical parking lotcan contaminate streams, estuaries, bays, and ground water supplies ifthe runoff from the vehicle parking lot is permitted to simply flow ontoand sink into the ground.

[0004] Considerably more attention and regulation has been devoted tothe purification of sewage water, referred to as point source pollution,than to the purification of surface runoff from parking lots and otherimpervious surfaces. However, the EPA has an effort underway forpreventing and regulating such non-point source pollution sources.

[0005] It would be very beneficial to have a device which requires nooutside power to purify parking lot and street runoff before it is addedto streams and the groundwater supply.

SUMMARY OF THE INVENTION

[0006] The present invention is a self contained surface waterpurification unit which requires no outside power because the surfacewater flows through it under its own gravity induced power. The entireunit is built into a conventional appearing catch basin, usually aconcrete vault in the shape of a rectangular prism. The catch basin isbuilt with essentially two chambers, each serving a particular function.

[0007] The first chamber is the inlet chamber, and surface water entersinto it high on an outside wall. The exit from the inlet chamber islocated above the bottom, typically about one third of the way up a wallwhich separates the inlet chamber from the second chamber, the settlingchamber.

[0008] The inlet chamber serves as both a floatation chamber and asettling basin. Contaminants which are heavier than water, includingstones, metal, and gravel, sink to the bottom of the inlet chamber,while oil and other floating debris float to the top of the water, wellabove the sediment that has settled to the bottom.

[0009] When the water level in the inlet chamber reaches above the exitof the inlet chamber which is located high enough above the bottom ofthe inlet chamber to permit a significant volume for accumulation of thelarge debris, the water begins flowing into the second chamber, thesettling chamber. The exit of the inlet chamber is located where it willusually be between the floating debris and heavier debris in the bottomof the inlet chamber, thus taking advantage of the natural tendency toseparate solids and liquids by density.

[0010] The settling chamber contains a lamella separator. Such lamellaseparators are constructed of multiple parallel plates oriented at anangle to the vertical, and they function to settle fine sediment out ofliquid moving up through the separator. The lamella separator ispositioned to occupy about one-half the volume of the upper portion ofthe settling chamber. Surface water entering the settling chamber fromthe inlet chamber flows directly into the lamella separator, and as thewater rises in the settling chamber, since the part of the settlingchamber other than the portion holding the lamella separator is closedoff by a partition, the water must go through the separator to leave thecatch basin. Water going into the separator enters low at one side nearthe edges of the parallel plates, and the water leaving the separatorexits high on the opposite side near the other edges of the plates.

[0011] As the surface water rises through the lamella separator, thefine sediment settles out and falls through the spacing between theplates at the bottom of the separator to the bottom of the settlingchamber where it accumulates. The outlet for the entire catch basin islocated in the upper portion of the settling chamber so that the watergoes through the lamella separator before reaching the exit of the catchbasin.

[0012] One structural feature in the catch basin operates as anemergency overflow. An overflow partition within the inlet chamber,parallel to and spaced from the wall dividing the two chambers forms athird partial chamber. The overflow partition extends down from the topof the inlet chamber to close to the exit of the inlet chamber. However,the divider wall between the chambers does not actually reach the top ofthe catch basin. Thus, if the inlet chamber becomes full, the waterspills over the divider wall and directly into the top portion of thesettling chamber, and the excess water leaves the catch basin withoutgoing through the lamella separator, but can not pick up the materialpreviously settled out. The location of the overflow partition close tothe divider wall also prevents most of the floating debris in the inletchamber from overflowing into the settling chamber, because only thatsmall amount of the floating debris between the divider wall and theoverflow partition has access to the overflow above the divider wall.

[0013] Nevertheless, to aid in the removal of the oil in any overflow,and also in the normal flow, an oil capturing “blanket” can also belocated within the portion of the settling chamber from which the liquidexits the catch basin. This blanket is a layer made of a hydrophobic,oil absorbing material, and the liquid flows over it before exiting.

[0014] The only maintenance required for the catch basin of theinvention is the cleaning out of the two chambers and the occasionalreplacement of the oil capturing blanket when it is used. Access holesare provided for this in the top of each chamber. Access to the floatingmaterial and the large debris in the inlet chamber is straightforwardsince a pipe lowered through the access hole in the top can easily reachthe floating material and the debris settled to the bottom. However, inthe settling chamber an access door is provided in the partition betweenthe upper and lower portions. When the access door is opened, a pipe canbe lowered all the way to the bottom to pump out the fine sediment. Theoil capturing blanket is also accessible through the access hole abovethe settling chamber.

[0015] The catch basin of the invention thereby furnishes a device toremove trash, oil, and both large and fine sediment, and the onlymaintenance it requires is the occasional removal of the accumulatedcontaminants. Furthermore, the lamella separator of the inventionreduces the horizontal area used for settling to 12 to 25 percent of thearea used by previously available simple gravity or single angular plateseparators.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a cross section view of the preferred embodiment of thecatch basin of the invention from a side of the catch basin orientedtransverse to the divider wall between the inlet and the settlingchambers.

[0017]FIG. 2 is a cross section view of the preferred embodiment of thecatch basin of the invention from a side of the settling chamber whichis at 90 degrees to the view of FIG. 1.

[0018]FIG. 3 is a perspective view of the settling chamber of theinvention showing the flow path from the lamella separator to the catchbasin exit.

DETAILED DESCRIPTION OF THE INVENTION

[0019]FIG. 1 is a cross section view of the preferred embodiment of thecatch basin of the invention from a side of the catch basin orientedtransverse to divider wall 18 between inlet chamber 20 and settlingchamber 22. For the preferred embodiment, catch basin 10 of theinvention is essentially an enclosure shaped as a rectangular prism.Thus, walls 12 and 14 are on opposite sides of the enclosure, the nearwall is removed for viewing the interior structure, and another wall 16closes off the far side of the enclosure.

[0020] Inlet chamber 20 is essentially an empty volume into which inletpipe 24 empties. Inlet pipe 24 is located near the top of inlet chamber20. The one structural feature within inlet chamber 20 is overflowpartition 26. Overflow partition 26 is simply a wall attached to andextending down from top wall 28 of catch basin 10 to the region nearopening 36 in divider wall 18. Overflow partition 26 is parallel todivider wall 18 and spaced from it sufficiently so that liquid rising ininlet chamber 20 will also rise within space 30 between overflowpartition 26 and divider wall 18.

[0021] Divider wall 18 actually does not meet top wall 28 so that aspace remains between them to form overflow 32. Thus, if, the water ininlet chamber 20 rises to the height of overflow 32 because, during anunusual event, there is excessive flow into catch basin 10, the waterspills over divider wall 18 into the top of settling chamber 22 as shownby arrow A in FIG. 1, and out through exit 42 of settling chamber 22, asshown in FIGS. 2 and 3 by arrow B. However, overflow partition 26prevents most of the debris and the liquids floating on top of the waterfrom being discharged from catch basin 10.

[0022] Inlet chamber 20 functions as both a settling basin and aflotation chamber. Heavy contaminants such as metal, stone, and gravelsettle to the bottom of inlet chamber 20, accumulate as large debris 34,and do not continue with the flow of the water. Furthermore, floatingdebris and liquids lighter than water, shown in FIG. 1 as scum 35, floatto the top of the liquid in inlet chamber 20.

[0023] Water normally leaves inlet chamber 20 and moves into settlingchamber 22 through opening 36 in divider wall 18. Opening 36 is locatedfar enough up divider wall 18 to define a volume at the bottom of inletchamber 20 to hold the anticipated quantity of large debris 34 and toallow only water to enter opening 36, so that no material is picked upfrom large debris 34 accumulated at the bottom of inlet chamber 20. Theslope of the bottom 37 of opening 36 prevents the accumulation of anysediment on bottom 37 of opening 36, and the edges of parallel lamellaplates 39 (FIG. 2) of lamella separator 38, which are mounted tightlyagainst opening 36, function as a bar screen to also block the entry oflarge debris into settling chamber 22.

[0024] The water flow moving through opening 36 has no significantvelocity since it is driven through opening 36 by only the slightpressure head of the water above opening 36 within inlet chamber 20. Inthe preferred embodiment of the invention, catch basin 10 has a totalheight of about 10 feet, and since the exit from settling chamber 22 islocated about a third of the way from the top of catch basin 10 whileopening 36 is located about a third of the distance from the bottom, thehead of pressure moving water through opening 36 is only about 3 feet atmost. The resulting low velocity permits the heavier contaminants toeasily sink to the bottom of inlet chamber 20.

[0025] As seen in both FIG. 1 and FIG. 2, as water, indicated by arrowC, flows through opening 36 into settling chamber 22, and after it fillsthe lower portion of settling chamber 22, it rises within lamellaseparator 38. Partition 40 and vertical partition 41 are located withinsettling chamber 22 between opening 36 and water exit 42 to prevent thewater from rising into exit 42 without first moving upward throughlamella separator 38.

[0026] As shown in FIG. 2 and well known in the literature, lamellaseparator 38 is constructed as a configuration of solid parallel plates39 oriented at an angle to the vertical with a small spacing between theplates. Vertical partition 41, through which parallel lamella plates 39are shown by dashed lines, closes off one side of lamella separator 38and divider wall 18 closes off the other side so that the water musttravel from the bottom to the top within lamella separator 38. Lamellaseparator 38 acts, as do other lamella separators, to cause finesediment 44, such as fine sand suspended in the surface water, to settleout and fall into the volume below the separator.

[0027]FIG. 3 is a perspective view of settling chamber 22 of theinvention, with the top wall and the near side vertical wall removed,showing the flow path from lamella separator 38 to catch basin exit 42.As best shown in FIG. 3 by the flow indicating arrows, as the waterrises through lamella separator 38, it moves above partition 40 and overthe top edge of vertical partition 41. It then leaves lamella separator38, flows across partition 40, below extension 43 of vertical partition41, and out of catch basin 10 through exit 42. Oil capturing blanket 56can easily be mounted on the sloped portion of partition 40, where thewater normally flows under below extension 43. When oil capturingblanket 56 is included in settling chamber 22, it furnishes andadditional opportunity to remove oil remaining in the water exitingcatch basin 10.

[0028] Thus, as the surface water moves through catch basin 10 of theinvention, three major contaminants are removed and separated. Heavymaterial accumulates in the bottom of inlet chamber 20. Floating debrisand liquids that are lighter than water accumulate on top of the waterin inlet chamber 20, and fine sediment accumulates in the bottom ofsettling chamber 22. Oil capturing blanket 56 offers the furtheropportunity to remove remnants of any oil remaining in the water.

[0029] The only regular maintenance required when using the invention isthe removal of the accumulated contaminants from catch basin 10 and theoccasional replacement of the oil capturing blanket. The removal of thecontaminants is accomplished quite simply by the use of a conventionalpump normally used to clean out such locations as street drains. The endof the pickup hose of such a pump is first lowered into inlet chamber 20through cleanout hole 46, lowered to the level of floating scum 35, andscum 35 is pumped out. The end of the pickup hose is then lowered fullyto the bottom of inlet chamber 20 and large debris 34 is pumped out.Finally, the end of the pickup hose is lowered through cleanout hole 48into the bottom of settling chamber 22, and fine sediment 44 is pumpedout. In order to permit the pickup hose to reach the bottom of settlingchamber 22, hinged door 50 in partition 40 is first manually opened byreaching through access hole 48 with a tool to engage handle 52 on door50. Cleanout hole 48 also provides access for the occasional removal ofoil capturing blanket 56.

[0030] The present invention thereby furnishes a simply constructedsurface water purifying catch basin which requires no outside power andonly routine maintenance. Moreover, the lamella separator of theinvention reduces the horizontal area used for settling to 12 to 25percent of the area used by previously available simple gravity orsingle angular plate separators.

[0031] It is to be understood that the form of this invention as shownis merely a preferred embodiment. Various changes may be made in thefunction and arrangement of parts; equivalent means may be substitutedfor those illustrated and described; and certain features may be usedindependently from others without departing from the spirit and scope ofthe invention as defined in the following claims.

[0032] For example, cleanout holes 46 and 48 can be furnished withsimple covers or can have attached cylindrical extensions which rise toground level above top 28 of catch basin 10, and they can be made largeenough for personnel to pass through them. Furthermore, inlet 24 andexit 42 can also be located on different walls of catch basin 10.

What is claimed as new and for which Letters Patent of the United Statesare desired to be secured is:
 1. A water purifying catch basincomprising: an enclosure with a bottom and a top wall and with theenclosure separated into an inlet chamber and a settling chamber by adivider wall; a water inlet permitting water to flow into the inletchamber from outside the catch basin; a water exit permitting water toflow out of the catch basin from the settling chamber, with the waterexit located no higher above the bottom of the catch basin than thewater inlet; a lamella separator located within the settling chamber sothat there is a volume below the lamella separator for accumulatingmaterial removed from the water by the action of the lamella separator;an opening in the divider wall to permit water to move from the inletchamber to the lamella separator, with the opening located high enoughin the divider wall to create a volume within the inlet chamber belowthe opening for collecting material which settles out of the water inthe inlet chamber; and a partition in the settling chamber with thepartition located between the opening in the divider wall and the waterexit and configured to prevent water from moving from the opening in thedivider wall to the water exit without passing through the lamellaseparator.
 2. The catch basin of claim 1 further including an overflowlocated high on the divider wall permitting liquid to flow from theinlet chamber into the settling chamber if the water in the inletchamber reaches the height of the overflow.
 3. The catch basin of claim1 further including at least two access holes in the top wall of thecatch basin, the access holes located to permit cleaning out theaccumulated material in both the inlet chamber and the settling chamber.4. The catch basin of claim 1 further including a door within thepartition in the settling chamber to permit access to the volume belowthe partition for clean out of the accumulated material in the settlingchamber.
 5. The catch basin of claim 2 wherein the overflow includes anoverflow partition comprising a wall in the inlet chamber with theoverflow partition attached to and extending down from the top wall ofthe catch basin to below the overflow in the divider wall, with theoverflow partition located adjacent to the divider wall but spaced farenough from the divider wall to permit water to rise between them. 6.The catch basin of claim 1 further including an oil capturing surfacelocated in the settling chamber and positioned so that liquid leavingthe lamella separator flows over the oil capturing surface beforeexiting the catch basin.